Some people think I'm paranoid. I wouldn't say so. It's just that I pay more attention to the potential worst case outcome that some. So when it comes to storage, I have a mirrored RAID array in my home server. The contents are backed up to a separate disk in the same machine. I also have an offsite backup in a datacentre.
My offsite backup machine died, and is now sat at home waiting for me to rebuild it. So it was somewhat alarming when my backup drive also died. Uncomfortable about running with less redundancy than normal, I immediately went out and bought a replacement drive. When checking the drives in the machine to see which one I needed to pull out, I noticed that one of the mirrored drives had also failed and the array was running in degraded state. Eeeek! Of my four levels of redundancy, three had failed. If I'd had fewer, I'd be screwed right now!
I'm not sure why I wasn't notified about the RAID failure. Normally I automatically get an email when the array enters a degraded state. That's something I need to look into. For now, the array is rebuilding. I'll fit the new backup drive when I get home this evening.